Polyalkylene succinimide lubricant additives

ABSTRACT

A lubricating oil dispersant made by reacting an aldehyde (e.g. isobutyraldehyde) with an amine (e.g. tetraethylenepentamine) under conditions to form a Schiff base which is then reacted with a hydrocarbon-substituted succinic acid, anhydride or lower alkyl ester.

BACKGROUND

Dispersants are conventionally used in engine lubricating oil to keepinternal parts clean and to prevent the accumulation of sludge. Manyeffective additives are known. One such additive that is usedcommercially is a polybutene-substituted succinimide of ethylenepolyamine (U.S. Pat. No. 3,172,892).

SUMMARY

It has now been discovered that very effective ashless dispersants foruse in lubricating oil can be made by reacting an aliphatichydrocarbon-substituted succinic compound with a Schiff base. Use ofhigh molecular weight aliphatic hydrocarbon substituents leads todispersants which also have viscosity index improving properties.

DESCRIPTION OF PREFERRED EMBODIMENTS

A preferred embodiment of the invention is a lubricating oil additivehaving dispersant properties which is a product made by a processcomprising (a) reacting about 0.5-10 moles of an aldehyde containing1-20 carbon atoms with about 1-2 moles of an aliphatic amine containing2-50 carbon atoms and 2-11 amine nitrogen atoms, at least one of whichis a primary amine group, at elevated temperature while distilling outwater formed in the reaction thereby forming a Schiff base and (b)reacting said Schiff base with about 0.5-5 moles parts of an aliphatichydrocarbon substituted succinic acid, anhydride or lower alkyl ester.

Aldehydes useful in making a Schiff base include any aldehyde which willreact with a primary amine group to form a Schiff base. The preferredaldehydes are the aliphatic aldehydes containing one to about 20 carbonatoms. Representative examples of these are formaldehyde, acetaldehyde,propionaldehyde, isobutyraldehyde, octanal, 2-ethylhexanal,2-ethyloctanal, n-eicosanal, furfural, glyoxal, malonaldehyde,glutaraldehyde, fumaraldehyde, and the like, including mixtures thereof.

The more preferred aldehydes are the aliphatic monoaldehydes containingabout 4 to 8 carbon atoms such as butyraldehyde, isobutyraldehyde,hexanal, 2-ethyl butyraldehyde, pentanal, isopentanal, heptaldehyde,octanal, 2-ethyl hexanal, and the like, including mixtures thereof.

Amines useful in the invention include those having at least one primaryamine group capable of reacting with an aliphatic aldehyde to form aSchiff base. Preferably, these are aliphatic polyamines containing about2-50 carbon atoms and 2-11 amine nitrogen atoms, at least one of whichis a primary amine group. Representative examples includeN,N-dimethyl-1,3-propanediamine, ethylenediamine, 1,4-butanediamine,1,6-hexanediamine, N-(aminoethyl) piperazine, N-(aminopropyl)piperazine, N-(aminoethyl) morpholine, ethanolamine and the like,including mixtures thereof.

A useful class of amines are the alkylene polyamines which can berepresented by the formula

    H.sub.2 N--R.sub.1 --NH--.sub.n H

wherein R₁ is a divalent aliphatic hydrocarbon containing 2-4 carbonatoms and n is an integer from 1-10. Representative examples of theseinclude ethylenediamine, 1,2-propylenediamine, 1,3-propanediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, hexaethyleneheptamine, dipropylenetriamine, andthe like, including mixtures thereof.

Another useful class of amines are the amines having the structure

    R.sub.2 --NH--R.sub.3 --.sub.p NH.sub.2

wherein R₂ is an aliphatic hydrocarbon group containing about 8-30carbon atoms, R₃ is a divalent aliphatic hydrocarbon group containing2-4 carbon atoms and p is an integer from 1-4. Representative examplesof these amines include N-tetradecyl ethylenediamine, N-octadecylethylenediamine, N-octadecenyl ethylenediamine, N-dodecylethylenediamine, N-(dodecylaminoethyl) ethylenediamine,N-(octadecenylaminobutyl)-1,3-butanediamine,N-(triacontylaminoethyl)ethylenediamine, and the like, includingmixtures thereof.

Most preferably, R₃ in the above formula is the group --CH₂ --CH₂ --CH₂-- and R₂ is an aliphatic hydrocarbon group containing 12-20 carbonatoms. Of these, the preferred amines are those in which p is 2 such asN-(octadecylaminopropyl)-1,3-propanediamine.

Another useful class of amines are the ether amines having the formula

    R.sub.4 --O--R.sub.5 NH--.sub.q H

wherein R₄ is an aliphatic hydrocarbon group containing about 1-30carbon atoms, R₅ is a divalent aliphatic hydrocarbon group containing2-4 carbon atoms and q is an integer from 2-4. Representative examplesof these ether amines are N-[3-(methoxy) propyl]-1,3-propanediamine,N-[3-(octyloxy)-propyl]1,3-propanediamine,N-[4-(butoxy)butyl]-1,4-butanediamine,N-[3-(decyloxy)propyl]-1,3-propanediamine,N-[3-(dodecyloxy)-propyl]-1,3-propanediamine,N-[2-(octadecyloxy)ethyl]ethylenediamine,N-[4-(eicosyloxy)butyl]1,4-butanediamine,N-[4-(triacontyloxy)-butyl]1,4-butanediamine,N-[3-[3-(hexyloxy)propylamino]propyl]-1,3-propanediamine,N-[3-[3-(dodecyloxy)propylamino]propyl]-1,3-propanediamine,N-[2-[2-(octadecyloxy)ethylamino]ethyl]ethylenediamine,N-[3-[3-(eicosyloxy)propylamino]propyl]-1,3-propanediamine, and thelike, including mixtures thereof.

Most preferably R₄ is an aliphatic hydrocarbon group containing 8-20carbon atoms and R₅ is the group --CH₂ --CH₂ --CH₂ --. Still morepreferably q is 2.

The third reactant is an aliphatic hydrocarbon-substituted succinicacid, anhydride or lower alkyl ester thereof. Of these the mostpreferred is the anhydride although the acid or ester can be used. Loweralkyl esters include methyl, ethyl, propyl, butyl, isobutyl, and thelike.

The aliphatic hydrocarbon substituent group is preferably a highmolecular weight group which provides oil solubility. For example, auseful molecular weight range is about 300-300,000.

One preferred class of hydrocarbon substituents which provides additiveshaving good dispersant properties are polybutenyl substituents having amolecular weight of about 500-10,000. Polybutenes in this molecularweight range are readily available. Heating a mixture of such polybuteneand maleic anhydride at 200°-250° C. will form thepolybutenyl-substituted succinic anhydride. This reaction may becatalyzed by chlorine or by peroxides.

Another class of aliphatic hydrocarbon substituents are theethylene/propylene copolymers which can include other co-monomers. Thesesubstituents preferably have a weight average molecular weight in therange of about 10,000-300,000 and more preferably 50,000-200,000. Use ofsuch substituted succinic compounds leads to additives having viscosityindex improving properties in addition to being dispersants.

The more preferable copolymer substituents are derived from a copolymercontaining about 25-60 weight percent ethylene units, about 30-74 weightpercent propylene units and about 1-10 weight percent non-conjugateddiene units. Such copolymers and methods for making them are describedin U.S. Pat. Nos. 3,551,336; 3,598,738; 3,790,480; and 3,691,078.

In a still more preferred embodiment the copolymer substituent containsabout 40-60 weight percent ethylene units, about 35-60 weight percentpropylene units and about 1-10 weight percent of non-conjugated dieneunits. The diene units can be any of those described in theabove-mentioned patents but preferably are derived from a diene selectedfrom the group consisting of 1,4-hexadiene, 2,5-norbornadiene,dicyclopentadiene and ethylidene norbornene, including mixtures thereof.

The copolymer-substituted succinic compound can be made in a mannersimilar to that used to make the polybutene-substituted succiniccompounds. Better results are obtained using a peroxide catalyst in thecase of the high molecular weight copolymers.

The Schiff base is pre-formed by mixing the aldehyde and amine andheating the mixture to distill out water formed in the reaction. Themole ratio of aldehyde to amine can vary over a wide range. A usefulrange in which to experiment is about 0.5-10 moles of aliphatic aldehydeper each 1-2 moles of aliphatic amine. More preferably, about 1-5 molesof aldehyde are used per mole of amine.

The Schiff base formation is preferably conducted in an inertwater-immiscible solvent which assists in water removal. Preferredsolvents include aliphatic and aromatic hydrocarbons such as hexane,heptane, octane, nonane, petroleum ethers, benzene, toluene, xylene, andthe like.

The Schiff reaction is conducted under conditions which will distill outwater formed in the reaction. This can be at a temperature of about70°-200° C. depending upon solvent and pressure. Preferably, thereaction is conducted at atmospheric pressure using a solvent having aboiling range of about 60°-120° C. This permits water removal underrather mild conditions.

Following formation of Schiff base, excess aldehyde and solvent can beremoved by heating the mixture under vacuum to distill out volatilecomponents. Excess amine can also be removed in this manner althoughthis is not necessary and not readily accomplished except in the case oflow molecular weight amines.

In the second stage, the Schiff base is reacted with aliphatichydrocarbon-substituted succinic acid, anhydride or lower alkyl ester.The mole ratio of reactants can vary over a broad range. A useful rangeis 0.5-5 moles of hydrocarbon-substituted succinic compound per each 1-2moles of initial aliphatic amine. A more preferred range is about 1-2moles of hydrocarbon-substituted succinic compound per each mole ofinitial aliphatic amine.

The aliphatic hydrocarbon substituted succinic compound is usually madein a mineral oil solvent such as hydrotreated neutral oil. Dependingupon solubility, the hydrocarbon-substituted succinic compound isgenerally about 5-70 weight percent of the oil solution. This oil is notremoved and functions as a solvent in the second stage reaction of theSchiff base with the hydrocarbon-substituted succinic compound.

The second stage is conducted at a temperature high enough to causeamide or imide formation but not so high as to cause decomposition ofthe reactants. A useful temperature range is about 80°-200° C. Thereaction is usually started at a low temperature of about 80°-100° C.and then gradually heated to about 150°-200° C. to complete thereaction. Some gelling may occur at the start of the reaction, but thisdisappears as the reaction proceeds.

In an alternative procedure which lessens the amount of gelling, thehydrocarbon-substituted succinic compound is used in the form of a halfester or acid-ester which is formed by reacting the succinic anhydridegroup with an alkanol, such as methanol, ethanol, propanol, butanol,hexanol, and the like. The ester group is displaced during the reactionand the resultant alkanol is distilled out.

The following examples illustrate how the additives are made.

EXAMPLE 1

This example show the preparation of a succinic anhydride grafted olefincopolymer.

In a reaction vessel was placed 2783 grams of hydrococracked SUS 80neutral oil and 358.3 grams of a copolymer of ethylene, propylene,1,4-hexadiene, and 2,5-norbornadiene having a weight average molecularweight of about 115,000. The mixture was stirred and heated at 220° C.until the rubbery copolymer dissolved. The mixture was cooled to 180° C.and 13.6 grams of maleic anhydride was added. This mixture was blanketedwith nitrogen and stirred at 180° C. for 20 minutes while graduallyadding a total of 2.4 grams of di-tert-butyl peroxide. Stirring wascontinued for one hour at 180° C. at which time 29 inches Hg vacuum wasapplied to remove volatiles. Infrared analysis showed the formation ofsuccinic anhydride groups.

EXAMPLE 2 First Stage-Schiff Base

In a reaction vessel was placed 50 ml heptane, 132.2 grams ofN-oleoylaminopropyl-1,3-propanediamine (Triamine T-Trademark, ArmakCompany) and 72.1 grams of isobutyraldehyde. The mixture was heated toreflux under nitrogen while water was removed using a Dean Stark trap.After three hours, a total of 14.5 ml. of water was collected. Vacuumwas then applied (29 inches Hg) to remove heptane and unreactedisobutyraldehyde. Infrared analysis showed the formation of a Schiffbase.

Second Stage

In a reaction vessel was placed 258.2 grams of the succinic-graftedcopolymer from Example 1.

This was stirred at 80° C. and 5.6 grams of the above Schiff base wasadded. The mixture initially gelled and was heated further to 180° C.and stirred at that temperature for three hours. It became fluid. Themixture was then cooled leaving a viscous additive having both viscosityindex improver and dispersant properties.

EXAMPLE 3

This example used an ester of the succinic-grafted copolymer rather thanthe anhydride.

In a reaction vessel was placed 249.5 grams of the succinicanhydride-grafted copolymer solution from Example 1. To this was added2.6 grams 1-hexanol. This mixture was stirred and heated at 125° C. forone hour to convert the succinic anhydride groups to half-ester groups.Then 5.2 grams of the Schiff base from Example 2 was added and themixture stirred and heated. It gelled slightly at 150° C. but thinnedout after 20 minutes at 160° C. Stirring was continued for two hours at160° C. and then 29 inches Hg vacuum was applied to remove volatilesleaving a viscous lube oil dispersant-VI improver.

EXAMPLE 4

In a reaction vessel was placed 208.4 grams of the succinic-graftedcopolymer solution from Example 1 and 2.0 grams of 1-hexanol. This wasstirred and heated at 130° C. to convert succinic anhydride groups tohalf-ester groups. It was then cooled and at 80° C., 2.3 grams of aSchiff base made from 2.6 grams of tetraethylenepentamine and 1.0 gramsof isobutyraldehyde were added. The mixture was stirred and heated to190° C. and stirred at this temperature for two hours. It was thenvacuum stripped and then cooled leaving 211.7 grams of a viscous veryeffective dispersant-VI improver.

EXAMPLE 5

In a reaction vessel was placed 100.4 grams ofN-(2-aminoethyl)-2-aminoethanol. To this was added slowly 72.0 grams ofisobutyraldehyde followed by 100 ml. toluene. The mixture was stirredand heated under nitrogen to reflux while distilling out water using aDean Stark trap. After 14 ml. of water was removed, an additional 72.2grams of isobutyraldehyde were added in two increments while continuingto remove water. The reflux temperature rose gradually to 130° C. and atotal of 34 ml. of water was removed. A 29 inch Hg. vacuum was appliedto remove toluene and other volatiles leaving a Schiff base.

In a reaction vessel was placed 2522 grams of 80 SUS neutral mineral oiland 324.7 grams of the same copolymer used in Example 1. The copolymerwas first cut into small pieces. The mixture was stirred at 220° C.under nitrogen for two hours to dissolve the rubbery copolymer. Thesolution was cooled to 180° C. and 12.3 grams of maleic anhydride wereadded. While stirring at 180° C. under nitrogen, 2.4 ml. ofdi-tert-butyl peroxide was added over a 22 minute period. Stirring wascontinued for 1.5 hours and then 28 inches Hg vacuum were applied toremove volatiles. Formation of succinic anhydride grafts was confirmedby infrared.

In a reaction vessel was placed 271.6 grams of the abovesuccinic-grafted copolymer and 2.4 grams of 1-hexanol. This was stirredone hour at 135° C. to convert the succinic anhydride groups tohalf-ester groups. Then 2.5 grams of the above Schiff base were addedand the mixture stirred at 150°-155° C. for 2.5 hours. A vacuum of 29inches Hg was applied and volatiles, including displaced hexanol, weredistilled out assisted by a nitrogen sparge. The product was a usefuloil additive.

Other dispersants of this invention can be made following the abovegeneral procedure. For example, use of a polyisobutylene-substitutedsuccinic anhydride will result in a polyisobutylene-substituted succinicSchiff base condensation product.

The effectiveness of the additive as a lubricating oil dispersant wasmeasured using a bench dispersancy test. In this test, an asphaltenesludge was made by air oxidation of 100 neutral oil using an ironnaphthenate catalyst. The oxidized oil containing precipitated sludgewas diluted with heptane to dissolve some more of the sludge. Theremainder was filtered off. The sludge-saturated filtrate stabilizedwith a small amount of butanol was used as the test sludge.

The test was conducted by mixing 1 ml. of sludge solution into 10 ml.100 neutral mineral oil containing various amounts of test additives.The test samples were left standing for 16 plus hours and then ratedvisually. The test criterion was the lowest concentration of dispersantthat prevents formation of a precipitate. Thus, the lower theconcentration the more effective is the dispersant. The sludge solutionwas standardized against a presently commercial dispersant VI improverfor comparisons. This commercial dispersant was effective down to 0.25weight percent giving a precipitate at 0.125 percent.

The following table shows the performance of various additives atdifferent concentrations.

    ______________________________________                                        Additive of                                                                             Additive Concentration (percent)                                    Example   0.06      0.125  0.25   0.5  1.0                                    ______________________________________                                        2         ppt       OK     OK     OK   OK                                     3         ppt       OK     OK     OK   OK                                     4         ppt       OK     OK     OK   OK                                     5         ppt       OK     OK     OK   OK                                     ______________________________________                                    

These results show that the additives were quite effective atconcentrations as low as 0.125 percent.

The additives are used in lubricating oil at a concentration whichachieves the desired level of dispersancy and VI improvement. They mayalso independently be used in combination with non-dispersant VIimprovers to achieve desired levels. This can usually be accomplished byadding about 0.2 to about 2.0 weight percent of active ingredient to theoil. In other words, 10 weight percent of a 10 weight percent active oilsolution of additive would add about one weight percent additive.

The additives can be used in mineral oil or in synthetic oils ofviscosity suitable for use in the crankcase of an internal combustionengine. Crankcase lubricating oils have a viscosity up to about 80 SUSat 210° F.

Crankcase lubricating oils of the present invention have a viscosity upto about SAE 40. Sometimes such motor oils are given a classification atboth 0° and 210° F., such as SAE 10W 40 or SAE 5W 30.

Mineral oils include those of suitable viscosity refined from crude oilfrom all sources including Mid-East, Gulfcoast, midcontinent,Pennsylvania, California, Alaska, North Sea, and the like. Variousstandard refinery operations can be used in processing the mineral oil.

Synthetic oil includes both hydrocarbon synthetic oil and syntheticesters. Useful synthetic hydrocarbon oils include liquid polymers ofα-olefins having the proper viscosity. Especially useful are thehydrogenated liquid oligomers of C₆₋₁₂ α-olefins such as α-decanetrimer. Likewise, alkylbenzenes of proper viscosity can be used, such asdidodecylbenzene.

Useful synthetic esters include the esters of both monocarboxylic acidand polycarboxylic acid as well as monohydroxy alkanols and polyols.Typical examples are didodecyl adipate, trimethylol propanetripelargonate, pentaerythritol tetracaproate, di-(2-ethylhexyl)adipate, dilauryl sebacate and the like. Complex esters prepared frommixtures of mono- and dicarboxylic acid and mono- and polyhydroxylalkanols can also be used.

Blends of mineral oil with synthetic oil are particularly useful. Forexample, blends of 10-25 weight percent hydrogenated α-decene trimerwith 75-90 weight percent 150 SUS (100° F.) mineral oil results in anexcellent lubricant. Likewise, blends of about 10-25 weight percentdi-(2-ethyl-hexyl) adipate with mineral oil of proper viscosity resultsin a superior lubricating oil. Also blends of synthetic hydrocarbon oilwith synthetic esters can be used. Blends of mineral oil with syntheticoil are especially useful when preparing low viscosity oil (e.g. SAE 5W20) since they permit these low viscosities without contributingexcessive volatility.

The more preferred lubricating oil composition includes zincdihydrocarbyldithiophosphate (ZDDP) in combination with the presentadditives. Both zinc dialkyldithiophosphates and zincdialkaryldithiophosphates as well as mixed alkyl-aryl ZDDP are useful. Atypical alkyl-type ZDDP contains a mixture of isobutyl and isoamylgroups. Zinc di-(nonylphenyl) dithiophosphate is a typical aryl-typeZDDP. Good results are achieved using sufficient ZDDP to provide about0.01-0.5 weight percent zinc. A preferred concentration supplies about0.05-0.3 weight percent zinc.

Another additive used in the oil compositions are the alkaline earthmetal petroleum sulfonates or alkaline earth metal alkaryl sulfonates.Examples of these are calcium petroleum sulfonates, magnesium petroleumsulfonates, barium alkaryl sulfonates, calcium alkaryl sulfonates ormagnesium alkaryl sulfonates. Both the neutral and the overbasedsulfonates having base numbers up to about 400 can be beneficially used.These are used in an amount to provide about 0.05-1.5 weight percentalkaline earth metal and more preferably about 0.1-1.0 weight percent.In a most preferred embodiment the lubricating oil composition containsa calcium petroleum sulfonate or alkaryl (e.g. alkylbenzene) sulfonate.

Other viscosity index improvers can be included such as thepolyalkylmethacrylate-type or the ethylene-propylene copolymer type.Likewise, styrene-diene VI improvers or styrene-acrylate copolymers canbe used. Alkaline earth metal salts of phosphosulfurized polyisobutyleneare useful.

Many preferred crankcase oils also contain supplemental ashlessdispersants such as the polyolefin-substituted succinamides andsuccinimides of polyethylene polyamines such as tetraethylenepentamine.The polyolefin succinic substituent is preferably a polyisobutene grouphaving a molecular weight of from about 800 to 5,000. Such ashlessdispersants are more fully described in U.S. Pat. Nos. 3,172,892 and3,219,666, incorporated herein by reference.

Another useful class of ashless dispersants are the polyolefin succinicesters of mono- and polyhydroxy alcohols containing 1 to about 40 carbonatoms. Such dispersants are described in U.S. Pat. Nos. 3,381,022 and3,522,179.

Likewise, mixed ester/amides of polyolefin substituted succinic acidmade using alkanols, amines and/or aminoalkanols represent a usefulclass of ashless dispersants.

The succinic amide, imide and/or ester type ashless dispersants may beboronated by reaction with a boron compound such as boric acid.Likewise, the succinic amide, imide and/or ester may be oxyalkylated byreaction with an alkylene oxide such as ethylene oxide or propyleneoxide.

Other useful ashless dispersants include the Mannich condensationproducts of polyolefin-substituted phenols, formaldehyde andpolyethylene polyamine. Preferably, the polyolefin phenol is apolyisobutylene-substituted phenol in which the polyisobutylene grouphas a molecular weight of from about 800 to 5,000. The preferredpolyethylene polyamine is tetraethylene pentamine. Such Mannich ashlessdispersants are more fully described in U.S. Pat. Nos. 3,368,972;3,413,347; 3,442,808; 3,448,047; 3,539,633; 3,591,598; 3,600,372;3,634,515; 3,697,574; 3,703,536; 3,704,308; 3,725,480; 3,726,882;3,736,357; 3,751,365; 3,756,953; 3,792,202; 3,798,165; 3,798,247 and3,803,039.

We claim:
 1. A lubricating oil additive having dispersant propertieswhich is a product made by a process comprising the steps of (a)reacting 0.5-10 moles of an aliphatic aldehyde containing 1-20 carbonatoms with 1-2 moles of a saturated aliphatic amine having 2-50 carbonatoms and 2-11 amine nitrogen atoms, at least one of which is a primaryamine group, at an elevated temperature high enough to distill out waterand within the range of 70°-200° C. to form an intermediate and (b)reacting this intermediate at about 80°-200° C. with about 0.5-5 moleparts of an aliphatic hydrocarbon substituted succinic acid, anhydrideor lower alkyl ester.
 2. An additive of claim 1 wherein said aliphatichydrocarbon substituent is a polybutenyl group having an averagemolecular weight of about 500-10,000.
 3. An additive of claim 2 whereinsaid aliphatic amine is an alkylene polyamine having the structure

    H.sub.2 N--R.sub.1 --NH--.sub.n H

wherein R₁ is a divalent aliphatic hydrocarbon having 2-4 carbon atomsand n is an integer from 1-10.
 4. An additive of claim 3 wherein saidaldehyde is an aldehyde having 1-12 carbon atoms.
 5. An additive ofclaim 2 wherein said aliphatic amine is an amine having the structure

    R.sub.2 --NH--R.sub.3 --.sub.p NH.sub.2

wherein R₂ is an aliphatic hydrocarbon group having 8-30 carbon atoms,R₃ is a divalent aliphatic hydrocarbon group having 2-4 carbon atoms andp is an integer from 1-4.
 6. An additive of claim 5 wherein R₂ is analiphatic hydrocarbon group having 12-20 carbon atoms, R₃ is the group--CH₂ --CH₂ --CH₂ -- and p is
 2. 7. An additive of claim 2 wherein saidaliphatic amine is an ether amine having the structure

    R.sub.4 --O--R.sub.5 NH--.sub.q H

wherein R₄ is an aliphatic hydrocarbon group having 1-30 carbon atoms,R₅ is a divalent aliphatic hydrocarbon group having 2-4 carbon atoms andq is an integer from 2-4.
 8. An additive of claim 7 wherein R₄ is analiphatic hydrocarbon group having 8-20 carbon atoms, R₅ is the group--CH₂ --CH₂ --CH₂ -- and q is
 2. 9. An additive of claim 8 wherein saidaldehyde is an aldehyde having 1-12 carbon atoms.
 10. An additive ofclaim 1 wherein said aliphatic hydrocarbon-substituted succinic compoundis formed by a process comprising reacting a maleic anhydride with anolefin copolymer having an average molecular weight of about10,000-300,000, said copolymer being derived from 25-60 weight percentethylene, 30-74 weight percent propylene and 1-10 weight percent of anon-conjugated diene.
 11. An additive of claim 10 wherein said copolymerhas a weight average molecular weight of about 50,000-200,000 and is acopolymer derived from 40-60 weight percent ethylene, 35-60 weightpercent propylene and 1-10 weight percent of a non-conjugated diene. 12.An additive of claim 11 wherein said non-conjugated diene comprises atleast one diene selected from the group consisting of 1,4-hexadiene,2,5-norbornadiene, dicyclopentadiene and ethylidene norbornene.
 13. Anadditive of claim 10 wherein said amine is an alkylene polyamine havingthe structure

    H.sub.2 N--R.sub.1 --N--.sub.n H

wherein R₁ is a divalent aliphatic hydrocarbon having 2-4 carbon atomsand n is an integer from 1-10.
 14. An additive of claim 13 wherein saidcopolymer has a weight average molecular weight of about 50,000-200,000and is a copolymer derived from about 40-60 weight percent ethylene,35-60 weight percent propylene and 1-10 weight percent non-conjugateddiene selected from the group consisting of 1,4-hexadiene,2,5-norbornadiene, dicyclopentadiene, ethylidene norbornene and mixturesthereof.
 15. An additive of claim 14 wherein said aldehyde is analdehyde having 1-12 carbon atoms.
 16. An additive of claim 10 whereinsaid aliphatic amine is an amine having the structure

    R.sub.2 --NH--R.sub.3 --.sub.n NH.sub.2

wherein R₂ is an aliphatic hydrocarbon group having 8-30 carbon atoms,R₃ is a divalent aliphatic hydrocarbon group having 2-4 carbon atoms andn is an integer from 1-4.
 17. An additive of claim 16 wherein R₂ is analiphatic hydrocarbon group having 12-20 carbon atoms, R₃ is the group--CH₂ --CH₂ --CH₂ -- and n is
 2. 18. An additive of claim 17 whereinsaid olefin copolymer has a weight average molecular weight of about50,000-200,000 and is a copolymer derived from about 40-60 weightpercent ethylene, 35-60 weight percent propylene, and 1-10 weightpercent of a non-conjugated diene selected from the group consisting of1,4-hexadiene, 2,5-norbornadiene, dicyclopentadiene, ethylidenenorbornene, and mixtures thereof.
 19. An additive of claim 18 whereinsaid aldehyde is an aldehyde having from 1-12 carbon atoms.
 20. Anadditive of claim 19 wherein said aldehyde is isobutyraldehyde.
 21. Anadditive of claim 10 wherein said aliphatic amine is an ether aminehaving the structure

    R.sub.4 --O--R.sub.5 NH--.sub.q H

wherein R₄ is an aliphatic hydrocarbon group having 1-30 carbon atoms,R₅ is a divalent aliphatic hydrocarbon group having 2-4 carbon atoms andq is an integer from 2-4.
 22. An additive of claim 21 wherein R₄ is analiphatic hydrocarbon group having 8-20 carbon atoms, R₅ is the group--CH₂ --CH₂ --CH₂ -- and q is
 2. 23. An additive of claim 22 whereinsaid copolymer has a weight average molecular weight of about50,000-200,000 and is a copolymer derived from about 40-60 weightpercent ethylene, 35-60 weight percent propylene, and 1-10 weightpercent of a non-conjugated diene selected from the group consisting of1,4-hexadiene, 2,5-norbornadiene, dicyclopentadiene, ethylidenenorbornene, and mixtures thereof.
 24. An additive of claim 23 whereinsaid aldehyde is an alkanal having 1-12 carbon atoms.